From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F88A2C11C4; Mon, 8 Jun 2026 20:18:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780949913; cv=none; b=hUtTYPsTBeGawN39b+YTCDfR3MGE5EAx4IvjttiWalYIkxpL/8G+6Xdl61kil1gKwHRoUzzQF/QNJAR6oqZl06h+gLTYpvDzCLaHGcy/iZRj4y3oG+Rw6Je9Gt5fOk3Qo1ieDwU1jlEus7E24cy83o9Zb0RavXTYpOPchjLOV+M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780949913; c=relaxed/simple; bh=RgxiUMC4Gg5WEF6siaaurrn4gvKK0Ztv89csTlsz4Vc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sK85aBCBeb3kxCjvesHNPzNDrvfvj/6bAv8ktVN3uw5nbGX5vP3RTuvitUURcTFy0IVuV8lGpcpmSxVNSOR8iTHvLEsu6+C1aH7pil143CEV/hbHofKcNLRuzqT8fFrCv2VyCKPnJrVs9y5CHcT/LIO77ttugpdnkjCBWERFqBU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bH7Q/qtw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bH7Q/qtw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AF141F00899; Mon, 8 Jun 2026 20:18:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780949911; bh=6pMIQ8hAJLYUSx6puyBFNWmCE2bhbXzI8u3T+QlW98w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bH7Q/qtw2xoewEu11bEzlRnojNrRvkK+OZa3g6sHTdP64XBgaW/jhpfC2QGo+Biz6 SPJNmtLKQDhKPKu+QrJemxqpJayW0SIznri0fvzLxyI0AsLAqq48R/PYSBmDxcJyuv 8/ow5XJRVolfo86dZ5dI1pVpZbkdfDg+3qNge23z/y3+k75cTaCMt+S91MbbcijqGP KfL2LqV5w5thRlrCtAyailDVrcjKv1oZFfUTZVI6Cb6c2w/nichk+Etd303ghKUDFY t3EB4zC9tSqH62/MiGtEobaTImIZUVyDY5mjrW3PogHvS/VctZjNlaBCms8rTMpMVG p6D6TEuAhG4FQ== From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , sashiko-bot , Song Liu , "Claude Opus 4.6" Subject: [PATCH 08/11] perf bpf: Use scnprintf() in snprintf_hex() and synthesize_bpf_prog_name() Date: Mon, 8 Jun 2026 17:17:48 -0300 Message-ID: <20260608201753.1979464-9-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260608201753.1979464-1-acme@kernel.org> References: <20260608201753.1979464-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo Both functions accumulate formatted output via ret += snprintf(buf + ret, size - ret, ...). If the buffer is too small and snprintf() returns more than the remaining space, ret exceeds size and the next 'size - ret' underflows, causing snprintf() to write past the buffer end. Switch to scnprintf() which returns the actual number of bytes written, making the accumulation safe. Fixes: 7b612e291a5affb1 ("perf tools: Synthesize PERF_RECORD_* for loaded BPF programs") Reported-by: sashiko-bot Cc: Song Liu Assisted-by: Claude Opus 4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf-event.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c index a27945c279efb779..2c09842469f1f28c 100644 --- a/tools/perf/util/bpf-event.c +++ b/tools/perf/util/bpf-event.c @@ -36,7 +36,7 @@ static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len) size_t i; for (i = 0; i < len; i++) - ret += snprintf(buf + ret, size - ret, "%02x", data[i]); + ret += scnprintf(buf + ret, size - ret, "%02x", data[i]); return ret; } @@ -140,7 +140,7 @@ static int synthesize_bpf_prog_name(char *buf, int size, const struct btf_type *t; int name_len; - name_len = snprintf(buf, size, "bpf_prog_"); + name_len = scnprintf(buf, size, "bpf_prog_"); name_len += snprintf_hex(buf + name_len, size - name_len, prog_tags[sub_id], BPF_TAG_SIZE); if (btf) { @@ -153,9 +153,10 @@ static int synthesize_bpf_prog_name(char *buf, int size, short_name = info->name; } else short_name = "F"; - if (short_name) - name_len += snprintf(buf + name_len, size - name_len, - "_%s", short_name); + if (short_name) { + name_len += scnprintf(buf + name_len, size - name_len, + "_%s", short_name); + } return name_len; } -- 2.54.0